1. Field of the Invention
The present invention is directed to an apparatus for conducting an endorectal prostrate biopsy procedure, and in particular to a device for such a procedure conducted using magnetic resonance (MR) supervision.
2. Description of the Prior Art
Pathological changes of the prostate are a very common disease not only in advanced age. An increasing number of prostate patients require a prostate biopsy since, left untreated, the prostate carcinoma metastasizes into the adjoining lymph nodes and bones and becomes incurable beyond a certain extent of the disease. In addition to supplying the PSA value (prostate-specific antigen) that is determined from the blood specimen, a biopsy supplies additional information that is absolutely necessary for evaluating benefits and risks of a surgery.
Heretofore, such a biopsy has been implemented substantially “blind,” under ultrasound supervision or as a multi-biopsy with up to 24 specimens. Frequently, however, pathological changes or the corresponding areas are visible only in an MR image.
A stereotactic attachment for a nuclear magnetic resonance tomography apparatus is proposed in German PS 43 25 206, but has not proven to be an improvement for endorectal prostate biopsy. German PS 43 25 206 describes an arrangement of apertured plates that is envisioned for a breast cancer biopsy, wherein the apertured plates can be moved toward and away from one another. The breast is compressed between the two plates, and the location at which a suspicious node is located is detected with appropriate imaging methods. Subsequently, a needle is applied exactly above this location and is pushed vertically downward. There is no mention of any sort of guide mechanism movable in space with which target region can be designationally approached, as is the case in prostate biopsy. The arrangement disclosed in German PS 43 25 206 accordingly, is completely unsuited for an endorectal prostate biopsy.
The same is true of an instrument guidance device for brain surgeries as proposed in U.S. Pat. No. 4,809,694. The guidance device disclosed therein allows an instrument to be swiveled in all possible directions on the basis of a ball bearing. This patent, however, does not provide any teachings as to how a specific, suspicious location is to be targeted with such an instrument in a prostate biopsy.